Valve system



3 Sheets-Sheet l l5 1 3 14 I9 I816 SylvanuS G'Shipley May 23, 1939. s.c. SHIPLEY VALVE SYSTEM Filed Nov. 19. 1934 s Sheets-Sheet 2 S ylvanusC. Shipley S. C SHIPLEY VALVE SYSTEM Filed No v. 19, 1934 3 Sheets-Sheet3 Sylvanus C. Shipley 167 Patented May 23, 1939 UNITED STATES PATENTOFFICE VALVE SYSTEM Application November 19,1934, Serial No. 753,557

g 14 Claim. This invention relates to valve systems for heaters whereina control valve is operated by an electric motor which is responsive toa condition such as temperature.

There are in existence at the present time, heating systems that employa heater delivering heat to a space and having a main heating burner, apilot burner and a safety pilot control cooperating with the pilotburner". It is usual to control the main burner by means of a controlvalve which is operated by an electric motor in response to change in acondition such as temperature as reflected by a room'thermostat; Themotor receives its energy in such systems from an electrical powor line.In somesystems, it is usual to have a secondary air controlling deviceincluding a lever extending outwardly through the control valve casingwhich is operated by the electric motor by being operatively connectedwith the control as valve for the main burner.

terns. when the'thermostat calls for heat,- the motor is energized toopen the control valve to supply fluid to the main burner which isignited by the pilot burner. Provision is made by means 25 of the safetypilot control whereby the motor may not be energized to open the controlvalve when the pilot burner is extinguished. In the above describedsystems, the power lines which deliver energy to the electric motor aresubject so to power failure and when the thermostat calls for heatduring this period of power failure, the motor cannot be energized toopen the control valve. 1

It.often happens that heat is required during 35 this period of powerfailurean'd some means must be provided'to open the control valve todeliver fluid to the main burner. In the case of the system utilizing asecondary air control mechanism, the means for controlling the secondary40 air control mechanism, which is operatively connected to the maincontrol valve and which extends outwardly through the casing thereof,forms a convenient means whereby the control 'valve' may be manuallyopened. In the case opened. Users of such systems have been properlyinstructed how to open thecontrol valvevmanually during the period ofpower failure and they In the above sys-" where no such secondary aircontrol mechanism have become so accustomed to dose that it has becomepractically automatic on their part.

In many instances, the failure of the control valve to open at thecommand of the thermostat is due to extinguishment of the pilot burneras reflected by the safety pilot control. Under such circumstances, ifthe control valve should be.

manually opened in the manner pointed out above, the main burner wouldnot ignite due to the pilot burner being extinguished, causing largeamounts of combustible fluid to accumulate in the heater.

Since the user has been properly instructed to manually open the controlvalve during periods of power failure in the manner pointed out above,it is entirely possiblethat he would attempt to open the control valvein the same manner during the period of extinguishment of the pilotburner and in the past such manual operation has occurred. Having thusopened the control valve and seeing that the main burner was notignited, he would probably determine that the pilot was not burning. Thechances are that he would attempt to light the pilot burner and in sodoling, he would unconsciously ignite the large amounts of combustiblefluid accumulated in the heater caused by the previous opening of thecontrol valve.- Under such conditions, explosions of no mean proportionare liable to occur much to the damage of the heater and possible injuryto the user.

Therefore, an object of this invention is to provide a manual means foropening the control valve which is not readily accessible to the userthereof and which requires the manual opening of the valve to be made bya properly instructed service man or prevents the haphazard openingthereof by the user.

Another object is to provide a motorized control valve having a coverenclosing the same and requiring the cover to be removed before saidcontrol valve may be'manually opened.

Still another object is to provide a motorized control valve having'acover enclosing the same K and an auxiliary control element extendingoutwardly therefrom forming a convenient means for manually opening thevalve with means located within the cover preventing fmanual opening ofthe valve without first removing the cover.

A further object is to provide a motorized control valve having a pawlconnecting said motor and said control valve whereby said control valveis opened by energization of said motor and to provide means on saidpawl to permit manual opening of said valve.

. control whereby a control valve may not be automatically or manuallyopened while the pilot is extinguished except by releasing said latchingmechanism.

A further object is to provide a manual con-- trol means for a valve incombination with the systemto be disclosed hereafter.

- Further objects and advantages will become apparent to those skilledin the art by reference to the accompanying description and drawings inwhich:

Fig. 1 is a vertical sectional view of the control valve assembly takensubstantially on the line II of Fig. 2,

Fig. 2 is an end elevational view of the same looking from the left inFig. l and showing the cover in section,

Fig. 3 is a sideelevational view looking from the right in Fig. 2, thecover being shown in section and the terminal block and binding postsbeing shown in broken lines as if transparent,

Fig. 4 is a diagrammatic view of the structure shown in Figs. 1 to 3 andincluding the electrical control system therefor,

Fig. 5 is a diagrammatic view similar to Fig. .4 but showing a modifiedform of the invention,

Fig. 6 is a schematic view of a system including the present inventionassociated with a gas burner.

The invention contemplates the use of the after-described control systemin combination with a heater, preferably a gas heater, having a mainburner, a pilot burner combined with a safety pilot control and asecondary air control which are old in the art and need not bespecifically shown and described, it being sufficient to state that thecontrol valve 9 controls the main burner, that the safety pilot controloperates the safety pilot switch arm |3| and that the lever 58 controlsthe secondary air supply.

Referring now to Figs. 1 to 4, the control valve generally designated at9 has a valve casing |8 having inlet and outlet openings II and I2respectively. The valve casing ID has a transverse wall l3 having a portopening l4 therein which isencompassed by an annular shoulder to form avalve seat l5. The valve member comprises a valve disc l6 adapted toseat on the annular seat l5, reinforcing washers I! and I8 flanking thevalve disc l6, said valve disc I 6 and said reinforcing washers I1 andI8 being securely clamped together by means of a plug l9 and a nut 29screwed thereon.

Extending into the plug |9 of the valve member is a valve stem 2|, theplug I9 and the valve stem 2| having holes to receive a pin 22 to securethe valve stem 2| and plug |9 together in fixed relation. Mounted in anannular groove in' the valve stem 2| is a split ring 23 which supports aspring retainer member 24. A spring 25 rests in the spring retainermember 24 and abuts against an abutment plate 26 to normally urge thevalve member toward its seat. Located adjacent the upper portion of thevalve casing H] are a disc 21, a packing washer 28 and a support 29which are secured together and to the abutment disc 26 by means ofrivets 38. 3| designates a clamping nut, screw-threaded on the upperportion of the valve casing H! to hold the. support 29 in fixed relationto the valve casing l8.

through which the valve stem 2| slidably extends outwardly from thevalve casing H]. In order to effectively seal the valve I0 againstleakage of fluid therefrom, a diaphragm 31 is secured to the outer endof the valve stem 2| by clamping the diaphragm 31 between a nut 34 and awasher 35, the clamping action being efiected by a nut 36 screwed on thescrew-threaded portion 33 of the valve stem 2|. The outer edge of thediaphragm 31 is clamped between the support 29 and a base 38 by means ofscrews 39.

Mounted on the base 38 by means of screws 42 are two upright, spacedparallel plates 48' and 4|, the plates 48 and 4| being held in spacedrelation by bolts 43 cooperating with nuts 45 to clamp the plates 40 and4| against spacer members 44.

A motor of any known type, generally designated at 48, is secured to andspaced from the vertical plate 48 by means of screws 41 and spacers 48.The motor shaft extends through the '.,plate 48 and has a motor pinion49 located on the end thereof. Located between the plates 48 and 4| anddriven by the motor pinion 49 is a reduction gear train, comprising agear 58 engaging the motor pinion 49, a gear 52 engaging a pinion 5|integral with the gear 58 and a gear 54 engaging a pinion 53 integralwith the gear 52. The gears and pinions are suitably mounted and spacedbetween the upright parallel plates 40 and 4| by means of bearings 55.

By means of a pivot pin 59 and spacers 50, a lever 58 is pivoted betweenthe plates 48 and 4| and by means of a pivot pin BI and spacers 32 thelever 58 is pivoted to a U-shaped bracket 63, which bracket 83 issecured to the valve stem 2| by a nut 64 screwed on the screw-threadedportion 33 of the valve stem 2| whereby movement of the lever 58 in aclockwise direction about its pivot pin 59 causes opening of the valve9.

Pivoted to the lever 58 by means of a pin 65 is an upwardly extendingpawl 66, havinga concave portion 61 to'engage and coact with a pin 68se-.

cured to the gear 54. The pawl 86 is urged inwardly by means of a spring18 engaging the pawl 66 and a pin 1| located on the lever 58 and inwardmovement of the pawl 86 1s limited by means of a stop pin 692 The outerend of the lever 58 is provided with holes 12 in which there may beattached means for controlling a secondary air supply to the heater.

The upright plate 40, has an inwardly extending flange 18 to which issecured a screw I6 by means of a nut 19. A cover 15 encloses the movingmechanism and is held in place by a knurled nut 11 screw-threaded on thescrew 16. The cover I5 has a slot 88 through which the lever 58 extendsoutwardly so that the lever 58 may actuate the secondary air control.

A sleeve 8| is suitably secured to the upright plate 4| and has slidablymounted therein a latch pin 82, having an annular flange;83 at the innerend thereof and a fibre disc 85 secured intermediate the ends thereof tobe engaged by a spring 84'to maintain the latch pin 82 in its outwardposition, the latch pin 82 extends outwardly through'a slot 86 in thecover 15 for external manual manipulation.

From the above description of the structure,

.it will be seen that when the motor 48 is energized, it operatesthrough the gear train to angularly move the pin 88 to engage theconcave surface 61 of the pawl 68 to raise the pawl 88 and therebypivotthe lever 58 about its pivot 59 to open the control valve 9. Upwardmovement of the valve member and the pivoted lever 58 is arrested by thelever 58 engaging against the stop pin 69 whereupon the motor is stalledand the valve 9 is maintained in open positionas long as the motor 46 isenergized. When the motor 46 is deenergized, the spring 25 closes thevalve 9 and returns the parts to their original positions.

61 designates an insulating terminal block which is secured to andspaced from the vertical plate H by means of screws 88 and spacers 89.Mounted onthe terminal block 81 are binding posts90, 9|, 92, 93, 94 and95. The-binding posts 90 and 9I are the power terminals and are nor-'mally connected to the secondary terminals of a step-down transformer,not forming part of the valve structure per se. The binding post 92 isconnected to a contact l30 of a safety pilot control and the binding"post 93 is connected to an upper stationary binding post I31 ofa roomthermostat I36. The binding post 94 is connected to an upper contact I35 of a room thermostat I36 and the binding post 95 is connected to alower contact I33 of a room thermostat I36 and to a switch arm I3I ofthe safety pilot control. 96 and 91 designate motor lead wires which areconnected respectively to binding posts 90 and 94,

- these motor lead wires being extended through a conduit tube 98located between the spaced upright plates 40 and 4|.

The shaft of the large gear 54 has an outwardly extending extension 99which is flattened to slidably receive two friction discs I so that whenthe shaft extension 99 is rotated, the friction discs are also rotated.Rotatably mounted on the extension 90 and located between the discs I00is a friction cam IOI which is held in frictional engagement with thefriction discs I00 by means of a spring I02 abutting against the outerfriction disc I00 and a collar I03 secured to the extension 99 by meansof a pin I04. I05 designates a stop pin secured to the upright plate 4|which coacts with abutments I06 and I0I of friction cam I M to limit theangular movement of the friction cam IOI.

The friction cam I 0| has a cam surface I08 which coacts with a camfollower I09 secured to a rocker IIO which is pivoted to the bindingpost 93 and spaced from the terminal block 8I'by means of a spacer I II.Secured to the rocker I I0 is a leaf spring II2 which engages astationary pin II3 secured to the terminal block 81 to urge the rockerH0 in a clockwise direction to maintain the cam follower I09 against thecam surface I08 of the friction cam IOI. Also secured to the rocker H0is a contact arm II4 having a contact III which engages at certain timeswith a coacting stationary contact II 6 secured to a bus bar III whichbus bar III is secured to the terminal block 81 by means of a screw H8.

The bus bar III is connected to the binding postv 94 and its lower endis bent inwardly and it has a stationary recycling contact II 9 on thisend which engages at predetermined times with a coacting movablerecycling contact I located on a spring bus bar I2I. The spring bus barI2I connects the binding post 9| and 92 and normally urges the contactI20 against contact H9. The fibre disc 85 of the latching pin 82 beingspring pressed outwardly normally separates the contacts H9 and I20 asis clearly shown in Fig. 2.

Located midway of the pawl 66 is a lug I which, under certain conditionsof operation, coacts with the stationary stop pin 69 to prevent upwardmovement of the lever 58 as will be more fully pointed out hereafter, Ahandle I42 is formed on the upper end of the pawl 66.

Fig. 4 is a diagrammatic showing of the essential elements of thisinvention, along with a wiring diagram showing the complete system. InFig. 4, it has been attempted to use the same reference characters as inFigs. 1 to 3 wherever possible. I22 and I23 are line wires carrying asupply of electrical energy which are connected to the primary I25 of astep down transformer I24. One end of the secondary I26 of the step downtransformer I24 is connected by a wire IT! to the field coil I28 of themotor, generally designated at 46, and the other end of the secondaryI26 is connected by a wire I29 to a stationary contact I30 of the safetypilot control. The contact I30 is engaged by a switch arm I3I of thesafety pilot control when the pilot burner .is burning and the switcharm I3I is connected to the stationary contact H6 and the movablecontact H5 is connected by a line wire I38 to the stationary bindingpost I31 of the room thermostat I36. engaged sequentially by movablecontacts I39 and I 40 secured to the room thermostat I36 since thedistance between contacts I33 and I39 is less than the distance betweencontacts I35 and I40.

Assume that'the control valve 9 is closed and the parts are in theposition shown in Figs. 1 to 3 and that the pilot burner is burningwhereby the safety pilot control causes the switch arm I 3| to engagethe contact I30. The room thermostat calls for heat moving the contactsI39 and I40 to the left but since the distance between contacts I33 andI39 is less than the distance between contacts I35 and I40, contact I39will first engage contact I33. Since the contacts H5 and II6 are open,the circuit to the motor is not completed. Upon further drop intemperature, contact I40 engages contact I35 completing a circuit fromthe secondary I26 through wire I29, contact I30 and switch arm I3I ofthe pilot safety control, bus I2I, wire I32, contacts I33 and I39,contacts I40 and I35, wire I34, wire 91, coil I28, and wire .I2'I backto the secondary I26 of the transformer I24, thereby energizing themotor 46 to begin its movement to open the valve 9. Upon this moven'etof the valve, cam IN is rotated in a clockwise direction and causes thecam surface I08 to' engage the cam follower I09 to close contacts H5 andH6 thereby completing a second and holding circuit from the secondaryI26 of the transformer- I24, through the wire I29, contact I30 andswitch arm I3I of the pilot safety control, bus I2I, wire I32, contactsI33 and I39, thermostat I36, binding post I3'I, wire I38,.contacts H5and H6, bus II'I, wire 91, field coil I28 and wire I2I back to thesecondary I26 of the transformer I24. Continued movement of the motor 46caused by this circuit raises the arm 58 about its pivot 59 tocompletely open the valve thereby delivering fluid to the heater whichis ignited by the pilot burner. When the valve is completely opened, thearm 58 engages the stop pin 69 to prevent further movement and to stallthe motor. As long as the room thermostat I36 calls for heat, the motorwill be energized and Stationary contacts I33 and I35 are will remain inthis stalled position and maintain the valve 9 fully opened. When thetemperature of the room rises sufficiently, the thermostat I35 moves thecontacts I45 and I39 to the right, breaking the above mentioned circuitsto deenergize the motor and allows the spring 25 to move the valve 9 toits closed position and to restore the parts to the position shown inFigs. 1 and 3.

If the pilot burner is extinguished, the safety pilot control moves theswitch arm I5I away from the stationary contact I3 and prevents theabove circuits from being completed. Therefore, when the pilot burner isextinguished, automatic opening of the valve by means of the motor 45 isentirely prevented.

Assume that there is a power failurein the lines I22 and I23 and theroom thermostat calls for heat, the valve 9 cannot be opened by themotor 55. Since the lever 58 extends outwardly through the slot 55 inthe cover I5 to control secondary air to the heater, this'extension ofthe lever 58 affords a convenient means for manually opening the valveby pressing down on the outward end of the lever 58 which swings thelever 58 about its pivot 59 to open the valve 9. In order to maintainthis valve 9 in its open position, the latch pin 82 is thrust inwardlyand engages under the lever 58 to hold the lever 55 in this shiftedposition and maintain the valve partially open such position being shownin broken lines in Fig. 3. Latch pin 82 is, prevented from being forcedoutwardly by the spring 84 by means of the flange 83 of the pin 82engaging the lever 58. By so moving the pin 82 inwardly, the fibre disc85 also moves inwardly allowing the recycling contact I25 to engagecontact II9. whereby a circuit is completed from the secondary I25 ofthe transformer l24, wire i29, contact I35 and switch arm i3I of thesafety pilot control, wire I2I, recycling contacts I25 and M5, wire 95,field coil I28 and wire i211 back to the secondary I25 of thetransformer I25. When the power failure period ends and power is againrestored to the lines I22 and H3, current will flow through this circuitto energize the motor to movethe lever 58 in clockwise direction aboutits pivot 55 which permits the annular flange of the latch pin 82 todisengage from the lever 58 to permit the sprin 84 to return the latchpin 82 to its outer position.

When the latch pin 82 is so returned to its outer position, the fibredisc 55 separates the contacts H9 and I25 to break the above circuit andif the room thermostat I35 is not calling for heat in the manneroutlined above, no other circuits will be completed and the spring 25will then close the valve I5 and return the parts to their relativepositions as shown in Figs. 1 and 3.

As pointed out above, great danger occurs from manually opening thecontrol valve when the pilot burner is extinguished because of thepermitting of large amounts of explosive fluid to flow into andaccumulate in the heater. In order to prevent the haphazard manualopening of the valve 9 bythe user of the heater without thought on hispart in determining the cause of the failure of the control valve '9 toopen whether it be power failure or the action of the safety pilotcontrol, the lug MI is provided on the pawl 55. This lug is so locatedwith relation to the stationary stop pin 59 that when the pin 58 of thegear 54 engages the concave surface 51 of the pawl 55, the

pawl 55 is angularly moved so that the lug I4I will not engage thestationary pin 59 which allows free easy opening movement of the valveI5 by the motor 45 as shown in broken lines in Fig. 4. However, manualmanipulation of the lever 55 in the manner pointed out above isprevented because the pawl 55 is urged inwardly by means of spring I5and by pushing down on the outward end of the lever 58 in the mannerpointed out above, lug II of the pawl 55 engages the pin 59 whichprevents movement of the lever 55 and consequent opening of the controlvalve 9. Therefore, in order to manually open the control valve 9, thecover I5 must be removed and the handle I52 of the pawl55 must begrasped to first swin the lug I4I to the left against the action of thespring I5 to clear the pin 69 to permit upward movement of the pawl 55and consequent opening of the valve 9.

By use of this construction, it is impossible for the user of the heaterand this system of control to manually open the valve in a haphazardmanner. The user must do one of two things either call a properlyinstructed service man who will be instructed to determine whether ornot the pilot burner is burning before he attempts to open the'maincontrol valve 9 or he must remove the cover l5 himself which will makehim think twice of what he is doing which will invariably make him lookto see if the pilot burner is burning before he attempts to manuallyopen the valve.

From the above, it will be seen that I have provided a control systemwherein there are manual means for opening the control valve which arenot easily accessible to the user of the system diagrammatically amodified form of my invention wherein like parts are indicated by likereferences. This modification employs the same motor 55, the same geartrain, the same lever 55 and the same valve 9. The control systemcomprises the same transformer I25, the same room thermostat I35, thesame friction cam 551i and the same recycling contacts H9 and I25.However, in this modification, the safety pilot control having thecontact I35 and the switch arm M is not placed in series as above but isplaced in parallel to operate a latching mechanism I5l which is securedto a stationary bracket E55. The pilot safety control embodying thecontact I35 and the switch arm- I3I and the coil I55 is connected inparallel to the rest of the control system by a wire E53 connectingcontact I35 with' the wire I29 by a wire I55 connecting the switch arm856 with a coil I 55 and by a wire I55 connecting the coil I55 with thewire I21. Bracket I55 is adapted to receive a solenoid coil I55 so thatwhen the coil I55 is energized, the latch arm I5I is attracted therebyin a clockwise direction to remove it from the path of lever 55. Aspring I52, located between the latch arm I5I and the support bracketI52, normally urges the latch arm I5I in the path of movement of thelever 58.

The manner of operation of this modification is identical to theoperation above when the room thermostat I35 calls for heat so adetailed decontrol valve 9 because the latch arm II is drawn out of thepath of movement of the lever 58' by the coil I55. However, when thepilot light is extinguished, switch arm I3I disengagescontact I30 tobreak the magnetic effect of coil I55 and the spring I52 urges the'latch arm I5I into the path 01 movement of the lever 58, preventingmanual opening of the control valve 9 and also preventing automaticopening of the control valve 9. Further, this modification contemplatesthe use of a pawl I49 which is not provided with the lug I 4I and thehandle I42 described above since the latching action is taken care of bythe latch arm I5I.

From the above, it is seen that in this modification I have devisedmeans whereby it is impossible to manually open the control valve 9 orto automatically open it by means of the motor 45 when the pilot burneris extinguished unless the cover 15 is removed and the latch arm I5I ismanually manipulated to remove it from the path of movement of the lever58.

In Fig. 6 the valve system of the present invention has been shown inconnection with a gas burning furnace. 'The valve 9 is shown in thisfigure as controlling the flow of gas through a pipe I66 to a gas burnerI61, this gas burner being located in a furnace generally designated bythe reference numeral I68. Primary air is admitted to the gas in theconventional manner by a suitable mixing chamber I69. A secondary airdamper I10 is provided which permits the closing off of the secondaryair upon the termination of burner operation to conserve heat in thefurnace. This secondary air damper is pivotally mounted and biasedinwardly. Connected to the damper is a chain "I, or other similardevice, which extends over pulleys I12 to the secondary air damper arm58. It will be obvious that upon the valve being operated, as previouslyexplained, so that the damper arm 58 is moved downwardly the secondaryair damp er I10 is permitted to move downwardly through the action ofgravity.

pilot burner I14 which is connected to the gas line I56 behind the valve9 so that it is normally constantly supplied with gas and henceconstantly lighted. The pilot burner previously referred to and shown inhighly schematic form is illustrated here. The pilot burner is shown ascomprising the bimetallic contact member I3I exposed to the heat of thepilot flame and which cooperates with thecontact I30. The roomthermostat I35 and the transformer I24 are shown in schematic form, sucha showing being considered to be adequate in view of the more detailedshowing in Figs. 4 and 5.

As many changes could be made in the above construction, installationand mechanism and as many apparent widely difierent embodiments of thisinvention could be made without departing from the scope thereof, it isintended'that all matter contained in the drawings or described in thespecification shall be interpreted as illustrative only and not in alimiting sense.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. In a device of the character described, a normally closed valve,automatic means associated with said valve for opening said valve, a

cover enclosing said .automatic means, means associated with saidautomatic means and ex- Located adjacent the main burner I61 Isasaidvalve may be manually opened, and latch means within said cover toprevent manual opening of said valve, said latch means being ineffectiveto restrain manual opening of said valve.

after a predetermined initial opening movement thereof. a

2. In a device of the character described, a normally closed valve,means mounting on said valve and including an electric motor for openingsaid valve, a cover enclosing said means, means connected to said meansand extending outwardly through said cover providing manual means foropening said valve, and releasable latch means within said cover toprevent manual opening of said valve when said cover is in place, saidlatch means being ineffective to restrain manual opening of said valveafter a predetermined initial opening movement thereof.

3. In a device of the character described, a normally closed valveautomatic means associated with said valve for opening said valveincluding a movable pin, a pawl associated therewith and a leverconnected between said pawl and said valve, and means associated withsaid pawl to prevent manual opening of said valve by manual manipulationof said lever, said last named means having no effect on the opening ofsaid valve by said automatic means.

4. In a device of the character described, a normally closed valve,automatic means associated with said valve for opening saidvalveineluding a movable pin, a pawl associated therewith and a leverconnected between said pawl and said valve, and means associated withsaid pawl to prevent manual opening of said Valve by manuaimanipulationof said lever but permitting manual opening of said valve by manualmanipulation of said pawl, said last named means having no eifect on theopening of said valve by said automatic means.

5. In a device of the character described, a normally closed valve, alever connected to said valve for operating the same, a pawl carried bysaid lever andhaving a lug thereon, an abutment in the path of movementof said lugto prevent opening of said valve by manipulation of saidlever, and a pin for engaging said pawl to swing said lug clear of saidabutment to move said lever to open said valve.

6. In a device of ,the character described, a normally closed valve,automatic meansassooiated with said valve for opening said valveincluding a movable pin, a pawl associated therewith and a leverconnected between said pawl and said valve, and releasable latch meansassociated with said lever to prevent manual opening of said valve bymanual manipulation of said lever, said latch means being inefiective torestrain manual opening of said valve after a predetermined initialopening movement thereof.

'1. In a device of the character described, a normally closed valve,automatic means associated with said valve for opening said valveincluding a movable pin, a pawl associated therewith and a leverconnected between said pawl and said valve, releasable latch meansassociated with said leverto prevent automatic opening of said valve bysaid automatic means and to prevent manual opening of said valve bymanual manipulation of said lever, and means to release said releasablemeans to permit automatic or manual opening of said valve, said latchmeans being ineffective to restrain manual opening of said valve after apredetermined initial opening movement thereof.

8.- In a control system comprising a heater a valve biased to closedposition for controlling said fuel inlet, power means associated withsaid valve for automatically opening said valve in response to acondition indicative of a demand for heat, means associated with saidpower means and operatively connected to said secondary air damper tocontrol the position of the same in accordance with the position of thevalve; and forming a convenient means for manually opening said valve,and releasable means to prevent manual opening of said valve by'manualmanipulation of said last named means, said releasable means having noeflect upon the opening of said valve by said power means.

9. In a control system comprising a heater having a fuel inlet and asecondary air damper, a valve biased to closed position for controllingsaid fuel inlet, power means associated with said valve forautomatically opening said valve in response to a condition indicativeof a demand for heat, a cover enclosing said power means, meanspositively connected to said valve and extending through said cover andoperatively connected to said secondary air damper to control theposition of the same in accordance with the position of the valve, saidlast named means forming a convenient means for manually opening saidvalve, and means to prevent manual opening of said valve by manualmanipulation of said last named means without removing said cover.

10. In a control system comprising a heater having a fuel inlet and asecondary air damper, a valve biased to closed position for controllingsaid fuel inlet, power means associated with said valve forautomatically opening said valve in response to a condition indicativeof a demand for heat, said power means including a movable .pin, a pawlassociated therewith and a lever connected between said pawl and saidvalve, said lever being operatively connected to said secondary airdamper and providing aconvenient means for manually opening said valveand means associated with said pawl to prevent manual opening of saidvalve by manual manipulation of said lever but permitting manual openingof said valve by manual manipulation of said pawl.

11. In a control system comprising a heater having a fuel inlet and asecondary air damper, a valve biased to closed position for controllingsaid fuel inlet, power means associated with said valve forautomatically opening said valve in response to a condition indicativeof a demand for heat including a lever connected to said valve, saidlever being operatively connected to said secondary air damper andproviding a convenient means for manually opening said valve, releasablemeans to prevent opening of said valve by said power means or by manualmanipulation of said lever and means to release said releasable means topermit opening of said valve, said releasable means being ineffective torestrain opening movement of said valve after an initial openingmovement thereof.

12. In adevice of the class described, a normally closed valve,operating mechanism for said valve including a motor and connectingmeans between said motor and said valve, a housing inclosing saidoperating mechanism, amember operatively connected and movable with saidapparatus, said member providing manual means for opening said valve,and a releasable latch efiective to prevent opening movement of saidvalve by actuation of said member but ineffective to prevent openingmovement of said valve by said operating mechanism.

13. In a control system comprising a heater having a fuel inlet and asecondary air damper, a valve biased to closed position for controllingsaid fuel inlet, power means associated with said valve forautomatically opening said valve in response to a condition indicativeof a demand for heat, a cover enclosing said power means, meansoperatively connected to said valve and extending through said cover andconnected to said secondary air damper to control the position of thesame in accordance with the position of the valve, said last named meansforming means for manually opening said valve, means to prevent openingof said valve by manual manipulation" without first removing said cover,said last named means having no effect upon the opening of said valve bysaid motor means.

14. In a control system comprising a heater having a fuel inlet and asecondary air damper, a valve biased to closed position for controllingsaid fuel inlet, power means associated with said the position of thevalve, said lever means also forming a means for manual operation ofsaid valve, means within said cover to normally prevent opening of saidvalve by manual manipulationof said lever means, said last named meanshaving no effect upon the opening of said valve by said motor means.

SYLVANUS C. SHIPLEI.

